The Navy fired the former commanding officer of the now-stricken mine countermeasures ship Guardian along with three of his officers after an investigation determined they “did not adhere to standard U.S. Navy navigation procedures,” the Navy said Wednesday.

Lt. Cmdr. Mark Rice, the ship’s CO, was fired Wednesday by Rear Adm. Jeffrey Harley, the commander of Expeditionary Strike Group 7. The reliefs came while Rice and his crew were to take charge of the replacement ship, the minesweeper Warrior, which arrived last week in Sasebo, Japan.

The reliefs included the second-in-command, Lt. Daniel Tyler, who also served as the navigator; the assistant navigator; and the officer standing watch as the officer of the deck at the time of the grounding. Officials declined to release the names of the other reprimanded junior officers, citing privacy laws.

“All four sailors were relieved by Rear Adm. Jeffrey Harley due to their role in the grounding and a loss of confidence,” the Navy’s press release said.

They have been temporarily assigned to ESG-7 pending the completion of the investigation.

The reliefs complicate the picture of the Jan. 17 grounding in the Philippines, which officials have so far blamed on an error on a digital chart that incorrectly plotted the Tubbataha Reef eight nautical miles from its actual location. Guardian ran hard aground and the crew of 79 was removed without injury. But the months-long saga, as Guardian’s fiberglass and wood hull pounded furiously against the coral while experts attempted to extricate it, was covered for weeks in the press and angered locals because the damage occurred in a National Marine Park, which has been designated a World Heritage Site by the United Nations.

The 7th Fleet commander, Vice Adm. Scott Swift, apologized four days after the incident.

The minesweeper was decommissioned on March 6 in Sasebo, Japan. Navy divers finished sawing through the hull and craning the cut-apart hull off the reef on March 29.